1. Field of the Invention
The present invention relates generally to terminals for connecting a first electrical interface to a second interface, such as a chip module to a printed circuit board (PCB), for providing a better circuit connection.
2. Background of the Invention
Integrated circuit (IC) devices, especially pin grid array (PGA) devices, are widely used in a zero insertion force connector or a low insertion force connector for building a signal transmission circuit between leads of a chip module and corresponding welding points of a printed circuit board. Conventional terminal having high contact performance described in U.S. Pat. Nos. 6,319,038 and 6,830,471 comprise a base portion extending uprightly, a pair of arm portions extending upwardly from the two sides of the base portion and bent opposite to each other, a solder portion disposed on a distal of the base portion, respectively. In use, the base portion of the terminal is positioned in corresponding receive holes of the insulative housing, and the arm portions are sandwiched between the leads of the chip module and the solder portions soldered with the contact pads of the printed circuit board; therefore, electrical connection between the chip module and the printed circuit board is achieved.
In order to enable high frequency signal transmission reliably between the chip module and the printed circuit board, matched impedance of the terminals to the leads of the chip module and the welded points of the printed circuit board should be met. However, said terminals described in the prior arts at least exist the following flaws: the impedance of the socket connector only relies upon the mechanical features of the base portion, the arm portion and the solder portion, which is difficult to match the impedance of the chip module and the printed circuit board. Moreover, while the developing trend of the socket connectors is high density and compact type, and the distances between the terminals of become narrower and narrower, which will produce signal disturbance between two adjacent terminals during signal transmission.
In view of the above, it is desired to provide a new socket connector to overcome the above-mentioned disadvantages.